package cn.lu.joke.util;


import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;

import android.util.Base64;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * @version V1.0
 * @desc AES 加密工具类
 */
public class AESUtils {

    private static final String KEY_ALGORITHM = "AES";

    private static final String IV = "CUSTOMGIVEDAPPIV";

    //密钥种子，用来生成密钥
    private static String key = "123456";

    //默认的加密算法
    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";

    /**
     * AES 加密操作
     *
     * @param content 待加密内容
     * @param key
     * @return 返回Base64转码后的加密数据
     */
    public static String encrypt(String content, String key) {
        return encrypt(content, getSecretKey(key));
    }

    /**
     * AES 加密操作
     *
     * @param content 待加密内容
     * @param secretKey
     * @return 返回Base64转码后的加密数据
     */
    public static String encrypt(String content, byte[] secretKey) {
        try {
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器

            byte[] byteContent = content.getBytes("utf-8");

            cipher.init(Cipher.ENCRYPT_MODE, getSecretKeySpec(secretKey));// 初始化为加密模式的密码器

            byte[] result = cipher.doFinal(byteContent);// 加密

            return Base64.encodeToString(result, Base64.NO_WRAP);//通过Base64转码返回
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return null;
    }

    /**
     * AES 解密操作
     *
     * @param content
     * @param key
     * @return
     */
    public static String decrypt(String content, String key) {
        return decrypt(content, getSecretKey(key));
    }

    /**
     * AES 解密操作
     *
     * @param content
     * @param secretKey
     * @return
     */
    public static String decrypt(String content, byte[] secretKey) {

        try {
            //实例化
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);

            //使用密钥初始化，设置为解密模式
            cipher.init(Cipher.DECRYPT_MODE, getSecretKeySpec(secretKey));

            //执行操作
            byte[] result = cipher.doFinal(Base64.decode(content, Base64.NO_WRAP));

            return new String(result, "utf-8");
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return null;
    }

    /**
     *
     *  转换为AES专用密钥
     *
     * @return
     */
    private static SecretKeySpec getSecretKeySpec(byte[] secretKey) {
        // 转换为AES专用密钥
        return new SecretKeySpec(secretKey, KEY_ALGORITHM);
    }

    /**
     * 生成加密秘钥
     * @param key
     * @return
     */
    private static byte[] getSecretKey(String key) {

        try {
            //返回生成指定算法密钥生成器的 KeyGenerator 对象
            KeyGenerator generator = KeyGenerator.getInstance(KEY_ALGORITHM);

            //AES 要求密钥长度为 128
            generator.init(128, new SecureRandom(key.getBytes()));

            //生成一个密钥
            SecretKey secretKey = generator.generateKey();

            return secretKey.getEncoded();
        }catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void main(String[] args) {
        String s = "hello,您好";

        System.out.println("s:" + s);

        String s1 = AESUtils.encrypt(s, key);
        System.out.println("s1:" + s1);

        System.out.println("s2:"+AESUtils.decrypt(s1, key));


    }

}
